Scenario: clone-from-submodule, with a macro in upstream's attributes

Upstream's own .gitattributes defines a macro. Git accepts macro definitions only in the top-level .gitattributes, which upstream's is in its own repository and in a submodule, but not in a splice's folder. A converted submodule and a plain clone alike would lose the macro's attributes, and no line above the folder can bring them back: both refuse, and leave the decision to you. This is a known gap (#311).

Monorepo, on main: no .gitattributes. vendor/a/ is a submodule of the upstream, checked out at add run.bat.
Upstream ($UPSTREAM, reached as https://git.example.com/a.git): a .gitattributes that defines crlf-text and gives it to .bat files, and run.bat committed with LF.

Output

setup.bash builds this state:

$ build_scenario scenario_upstream_macro https://git.example.com/a.git

$ cat vendor/a/.gitattributes
[attr]crlf-text text eol=crlf
*.bat crlf-text

In the submodule, a repository of its own, the macro applies, and run.bat is checked out with CRLF (^M):

$ git -C vendor/a check-attr text eol -- run.bat && cat -A vendor/a/run.bat
run.bat: text: set
run.bat: eol: crlf
echo run^M$

Asked from the top of the monorepo, as checkout and git add ask once vendor/a is a folder, Git rejects the definition, and the attributes are gone:

$ git check-attr text eol -- vendor/a/run.bat
[attr]crlf-text text eol=crlf not allowed: vendor/a/.gitattributes:1
vendor/a/run.bat: text: unspecified
vendor/a/run.bat: eol: unspecified

So the conversion refuses, without a line to add:

$ git splice clone --from-submodule vendor/a
===  vendor/a: fetching https://git.example.com/a.git
!!   vendor/a: Git would check out or store some of its files otherwise than in upstream, and unsetting attributes above it can't change that
[1]

And so does a plain clone of the same upstream:

$ git splice clone https://git.example.com/a.git vendor/b
===  vendor/b: fetching https://git.example.com/a.git
!!   vendor/b: Git would check out or store some of its files otherwise than in upstream, and unsetting attributes above it can't change that
[1]

Output​

Output